1. Technical Field of the Invention
The present invention relates to an ink ribbon, a cartridge containing the ink ribbon and a method of discriminating a failure location from an ink ribbon base film when the failure occurs on the ink ribbon.
2. Description of the Related Art
Generally, an ink ribbon used in a thermal transfer printer is manufactured from ink ribbon base film. The ink ribbon base film is manufactured by applying a back coat layer to a back of a thin film as a film base material with a thickness of approximately a few .mu.m made of polyethylene and others, applying an undercoat layer to a surface of the film and coating the undercoat layer with ink material by a gravure coater and others to form an ink layer. Next, the above ink ribbon base film is cut into plural columns (for example, into three columns) and then three small windings called a pancake are made therefrom. Each of the ink ribbons is manufactured from the pancake by winding the film of pancake on a spool.
The ink layer contains sublimation-type ink and a thermal head sublimates the ink by heating it via the film base material. In printing, the sublimated ink is transferred and fixed on paper to receive an image, said paper being closely touched to the ink layer. At that time, as a quantity of sublimated ink can be controlled based upon a quantity of heat applied to a thermal head, continuous gradation can be applied to the density of printing.
In the above ink ribbon, however, failure such as the unevenness of each color ink often occurs in an ink ribbon manufactured using a specific column of ink ribbon base film. A column of the ink ribbon base film from which the failed ink ribbon is manufactured cannot be discriminated only by looking at the failed ink ribbon. As a result, when the failure occurs in an ink ribbon, a column in which the failure occurs cannot be discriminated from the plural columns of the ink ribbon base film.